Marathon Oil Foresees ‘Mass Layoff’ Amid ConocoPhillips Takeover

Marathon Oil Corp. warned of a “mass layoff” involving more than 500 employees at its Houston headquarters as part of the $17 billion takeover by ConocoPhillips, according to state filings.

The affected workers “may reasonably expect to experience a permanent loss of employment during the 12-month period” following closure of the transaction, Marathon said in a notice to the the Texas Workforce Commission released on Wednesday.

The date of the layoffs was listed in a state database as May 28, the day before the merger was publicly announced, although the full filing indicates the reductions are in may cases ...